JP3279730B2 - Hybrid crosslinked resin composition having good storage stability and molding method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin composition having the heat resistance and high rigidity of an unsaturated polyester resin and the impact resistance of a polyurethane resin at the same time, and a reaction injection molding method therefor. More specifically, it is stable as a two-pack type resin composition, has a liquid flow property capable of coping with a large-sized molded product, and has a curing time capable of injecting the resin, and is very easy to handle in storage or in the molding process A composition is provided.

[0002]

2. Description of the Related Art Unsaturated polyester resins have been widely used in housing equipment such as bathtubs and water storage tanks, as well as in the marine, industrial, and leisure fields due to their excellent rigidity and heat resistance. Since the molding hardening time is considerably long, the development to automobile parts is relatively small except for the sheet molding compound (SMC). On the other hand, polyurethane resins are widely used in automobile parts such as bumpers by a reaction injection molding method (RIM method) due to their excellent impact resistance and high-speed reactivity, but due to lack of strength. The types of parts used were limited.

[0003] Therefore, it has been attempted to combine an unsaturated polyester resin and a polyurethane resin to compensate for the disadvantages of both, and to produce a resin having a new structure. For example, a technology for producing a tough SMC by reacting a low acid value isophthalic acid-based unsaturated polyester with liquid MDI (Japanese Unexamined Patent Publication No.
No. 5-73718), a technique for obtaining an insoluble and infusible thermosetting product from ester and TDI by using the RIM method (JP-A-58-91719), and hydroxyacrylate. Technology for rapid in-mold polymerization from MDI (Japanese Patent Application Laid-Open No. 57-182,312), and molding speed and linear expansion coefficient of isophthalic unsaturated polyester containing terminal OH group and liquid MDI using RIM molding method. A technique (Compposites-No3-Mai-Juin1987) for obtaining a hybrid resin having excellent impact resistance and abrasion resistance has been reported.

[0004] However, the molding method by the RIM method is a two-component system, in which a resin component and an isocyanate component are respectively charged into a machine tank, and the raw material components once charged into the machine tank are used on the same day. It is premised that the operation is performed, but there is a case where it remains, and as a further inconvenience, there is a case where the machine tank stays in the machine tank for about two weeks due to a long-term stop. Therefore, the resin component and the aromatic polyisocyanate component once blended are stable for at least two weeks or more, and there must be no change in quality. Further, the isocyanate group reacts with moisture in the air to cause deterioration of the quality, so that it is usually avoided to mix other components in the molding process, and the aromatic polyisocyanate previously mixed from the manufacturer is used. It is common to accept and use it as is. On the other hand, resin components are not sensitive to moisture in the air, so in the urethane industry, other components are generally blended with resin components, and if they have a storage stability of about two weeks or more, There is no problem in producing molded products. Therefore, in the case where a resin component that has been previously blended is supplied, it is desirable that the storage stability be at least two weeks, preferably about one month.

[0005] In the unsaturated polyester / urethane hybrid crosslinkable resin, the presence of an organic peroxide which promotes radical polymerization in a mold (mold temperature of 50 to 70 ° C) and a decomposition accelerator thereof simultaneously with the urethanization catalyst are considered. is necessary. Combinations of organic peroxides and their decomposition accelerators have been known for a long time, but the most famous combinations include benzoyl peroxide and dimethylaniline, and methyl ethyl ketone peroxide and cobalt naphthenate. However, benzoyl peroxide decomposes in the isocyanate, elimination of the urethanization reaction between the isocyanate group and the OH group at 20 to 25 ° C. in a few days, and makes it impossible to carry out hybrid crosslinking. Also, methyl ethyl ketone peroxide reacts with isocyanate groups only by being added to aromatic polyisocyanate to cause gelation. Dialkyl peroxides are stable in aromatic polyisocyanates, but no suitable decomposition accelerator has been found. Also, cumene hydroperoxide, which has very good thermal stability, has the disadvantage that it reacts in the aromatic polyisocyanate.

[0006] For the reasons described above, a practical use of the hybrid cross-linking type is that an organic peroxide is added to isocyanate at the time of use, and all is used up after being charged into a machine tank. A so-called three-pack type (resin component, aromatic polyisocyanate component and curing agent component) has to be used, which has been a troublesome problem in handling and blending of raw materials. In addition, the condition is that the liquid flowability and the reaction start time longer than the resin injection time, the reactivity after the resin injection is good, and the demolding time of the molded article are short, which can correspond to a large molded article. That is, there has been a demand for the development of a stable raw material having good liquid flowability, in which a raw material delivered in a two-pack type can be directly charged into a machine tank and used.

[0007]

The problem to be solved by the present invention is to provide a hybrid crosslinked resin composition having good liquid flowability and storage stability that can be used for large-sized molded articles. Is stable to temperature, impact, etc., and stably exists in the aromatic polyisocyanate.
It is stable to humidity, etc., and stably exists in the resin component, and furthermore, when a decomposition accelerator is added to the resin component, it has stability such that it does not react with other components. An object of the present invention is to provide a two-component hybrid cross-linkable resin composition satisfying the conditions and a molding method.

[0008]

DISCLOSURE OF THE INVENTION As a hybrid cross-linkable resin, the present inventors have prepared a liquid flow property and storage stability in which an organic peroxide and a decomposition accelerator have been previously added to an isocyanate component and a resin component, respectively. As a result of intensive studies with the aim of obtaining a two-component hybrid cross-linked resin having a good
The inventors have found that they have a storage stability of more than one week, and have completed the present invention.

That is, the present invention provides: 1) an acid value of 2 mgKOH / g or less, and an OH value of 90 to 150;
The main component is a mixture of an unsaturated polyester having a terminal hydroxy group of mg KOH / g and a vinyl compound, which contains 0.1 to 0.6% by weight of cobalt naphthenate and 0.01 to 0.2% by weight of cobalt acetylacetone. The resin component (1) thus obtained and the aromatic polyisocyanate component (2) containing 2.0 to 8.0% by weight of a peroxyester as an organic peroxide are combined with a hydroxy group and an isocyanate.
OH / NCO = 1: 0.8-1: 1.
It has a good storage stability, characterized in that it is used in a ratio of 5, and the urethanization reaction between a hydroxy group and an isocyanate group and the radical crosslinking reaction with an unsaturated group can proceed substantially simultaneously. Hybrid crosslinked resin composition. 2) The resin composition according to 1), wherein polyethylene glycol is used as a dissolving agent for cobalt acetylacetone. 3) The resin composition according to 1), wherein t-butyl peroxy laurate is used as the peroxy ester. 4) Acid value 2 mgKOH / g or less, OH value 90-150 m
A mixture of a gKOH / g unsaturated polyester having a terminal hydroxy group and a vinyl compound as a main component, containing 0.3 to 1.0% by weight of cobalt naphthenate and 0.1 to 0.3% by weight of acetylacetone. 1. Resin component (1) and peroxyester which is an organic peroxide
The aromatic polyisocyanate component (2) contained in an amount of 0 to 8.0% by weight was prepared such that the equivalent ratio of the hydroxy group to the isocyanate group was OH / NCO = 1 / 0.8 to 1 / 1.5. A hybrid cross-linking type wherein a urethanation reaction between a hydroxy group and an isocyanate group and a radical cross-linking reaction with an unsaturated group proceed substantially simultaneously using a reaction injection molding machine. Resin molding method. 5) The molding method according to 4), wherein polyethylene glycol is used as a dissolving agent for cobalt acetylacetone. 6) The molding method according to 4), wherein t-butyl peroxy laurate is used as the peroxy ester. It is.

The unsaturated polyester having a hydroxyl group at the terminal that can be used in the present invention is, for example, an α, β unsaturated dibasic acid such as maleic acid, fumaric acid, itaconic acid or citraconic acid, or an anhydride thereof. With phthalic acid, isophthalic acid, terephthalic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, tetrahydrophthalic acid, a mixture with a dibasic acid such as chlorendic acid, ethylene glycol, propylene glycol, It is a condensation reaction product obtained by reacting glycols such as diethylene glycol, triethylene glycol, neopentyl glycol and the like by a conventional method to form an ester. In addition, as the vinyl compound, styrene, vinyl toluene, divinylbenzene,
There are methyl methacrylate, diallyl phthalate and the like,
These vinyl compounds are usually used in the form of a diluent by diluting and mixing about 15 to 50% by weight in the resin component. The most preferred unsaturated dibasic acid is maleic anhydride, and the optional dibasic acid is preferably isophthalic acid. As the glycols, ethylene glycol and diethylene glycol are preferred.

The dibasic acid / glycol molar ratio is dibasic acid / glycol = 1 / 1.2 to 1 / 1.5 and esterification is carried out by a conventional method, and the acid value is 2 mgKOH / g or less. Preferably, the reaction is terminated when the amount becomes 1 mgKOH / g or less. At this time, the hydroxyl value is 100 to 150 mg KOH
/ Mg range. After the reaction is completed, the viscosity is 1000cp
The mixture is diluted with a vinyl compound so as to have a s / 25 ° C. or lower. The most preferred vinyl compound is styrene.

[0012] When the acid value is 2 mgKOH / g or more, the urethane-forming reaction is delayed during the hybrid crosslinking reaction, and a good molded product cannot be obtained. Hydroxyl value is 100mgK
If it is OH / g or less, the viscosity becomes high, and the dilution ratio with styrene increases, so that only a brittle molded product can be obtained.
On the other hand, when the hydroxyl value is 150 mgKOH / g or more, the molecular weight of the unsaturated polyester becomes small, and only a soft molded article can be obtained.

The aromatic polyisocyanate which can be used in the present invention includes phenylene diisocyanate,
Tolylene diisocyanate (TDI), 4,4'-methylenebis (phenyl isocyanate) (MDI), carbodiimide-modified liquid MDI, NCO-terminated MDI modified by reaction with a polyol compound, polymethylene Polyphenylene polyisocyanate (Crude M
DI) and the like. Most preferred is carbodiimide-modified liquid MDI.

The organic peroxide which can be used in the present invention is of the peroxyester type, such as t-butyl peroxy 2-ethylhexanoate, t-butyl peroxy laurate, t-butyl peroxyoxylate. Butyl peroxybenzoate and the like can be mentioned. The most preferred peroxyester is t-butyl peroxylaurate. The amount of t-butyl peroxylaurate added to the aromatic isocyanate is in the range of 2.0 to 8.0% by weight. If the addition amount is 2.0% by weight or less, satisfactory crosslinking cannot be obtained due to insufficient radical crosslinking during the hybrid crosslinking reaction. If the content is 8.0% by weight or more, the effect of accelerating the radical cross-linking reaction is no longer saturated, and even if it is added, not only a better effect is not obtained, but also a factor that delays the radical cross-linking reaction.

The decomposition accelerator that can be used in the present invention is a combination system of cobalt naphthenate and cobalt acetylacetone. The addition amount of cobalt naphthenate is 0.1 to the resin.
1 to 0.6% by weight, more preferably 0.3 to 0.
5% by weight. When the content is less than 0.1% by weight, radical crosslinking is insufficient during the hybrid crosslinking reaction, and a good molded product cannot be obtained. If the content is 0.6% by weight or more, reaction control becomes extremely difficult. The amount of cobalt acetylacetone added is 0.01 to 0.2% by weight based on the resin. More preferably, it is 0.03 to 0.10% by weight. 0.01
Below, at the time of the hybrid cross-linking reaction, radical cross-linking is insufficient and a good molded product cannot be obtained. 0.2% by weight
Above, storage stability decreases. The solubility of cobalt acetylacetone in unsaturated polyester is low.
Therefore, use a dissolving agent. As a solubilizer,
A compound having 3 or less hydroxy functional groups, such as methanol, ethanol, polyethylene glycol, and polypropylene glycol. However, polyethylene glycol is preferred in terms of solubility.

As other components that can be used in the present invention, low molecular weight glycols and the like can be added if necessary. As low molecular weight glycols, ethylene glycol,
Trimethylolpropane, glycerin and their alkylene oxides. As other auxiliaries, those generally used in the unsaturated polyester industry, RIM urethane industry, etc., such as surfactants, interface modifiers, pigments, internal release agents, inorganic fillers, etc. can be used. .

The resin composition of the present invention thus obtained comprises a resin component and an aromatic polyisocyanate component.
It is a liquid material system and is injection molded into a mold by the RIM method. The mold can be filled with a reinforcing material if necessary. As a reinforcing material, a continuous strand mat is effective.

[0018]

The present invention will be described below with reference to examples. Tables 1 and 2 summarize the results of Examples and Comparative Examples. Parts in the examples represent parts by weight.

[0019]

[0020]

First, a mixture of an unsaturated polyester resin as a resin component and a vinyl compound was produced as follows. In a reactor equipped with a stirrer, thermometer and partial condenser, 42.0 kg of maleic anhydride and 3 parts of isophthalic acid were added.
After adding 5.6 kg, 21.5 kg of ethylene glycol and 59.9 kg of diethylene glycol, the inside of the system was replaced with nitrogen gas. The temperature was raised and reacted at 210 ° C. for 14 hours. At this time, the acid value was 0.8 mgKOH / g, and the hydroxyl value was 110 mgKOH / g. Then, 47.9 kg of styrene was added to 143.6 kg of the unsaturated polyester resin.
kg and 38.3 g of hydroquinone.

Examples 1 and 2 Comparative Examples 1 and 2 A mixture of the above-mentioned unsaturated polyester resin having a terminal hydroxy group and a vinyl compound as a resin component, and a carbodiimide-modified liquid MDI as an aromatic polyisocyanate
(Mitsui Toatsu Chemical Co., Ltd., product name Cosmonate LK, All NC
O 28.3%) was blended at the ratio shown in Table 1, and the storage stability was examined. The storage condition was determined by storing the sample in a room at 23 ° C., mixing and stirring each component at regular intervals according to the mixing ratio, and examining the reactivity. Acetylacetone cobalt (manufactured by Nippon Kagaku Sangyo Co., Ltd., trade name: Narsem Cobalt Co., Ltd.) was used by dissolving polyethylene glycol (trade name: PEG-400, manufactured by NOF Corporation). The results are shown in Table 1. In the case of using acetylacetone as in Comparative Example 1, and the most commonly used benzoyl peroxide / dimethylaniline system as in Comparative Example 2, the reaction activity was extremely high. On the other hand, it can be seen that in Examples 1 and 2 of the present invention, the reaction activity did not decrease even after 20 days of blending.

Example 3 The resin component and the isocyanate component used in Example 1 were charged into a machine tank of a high-pressure foaming machine LMR-228 manufactured by Toho Machine Industry Co., Ltd., and injection-molded into a mold under the conditions shown in Table 2. . The mold was a 535 × 200 × 3 mm sheet mold and was kept at 70 ° C. A continuous strand mat (Unifilo U-816, manufactured by Nippon Electric Glass Co., Ltd., weight per unit area: 375 g / m ² ) was set in the mold to a predetermined amount. The obtained hybrid cross-linked resin molded product exhibited excellent physical properties as shown in Table 2.

[0024]

The hybrid crosslinked resin molded product of the present invention has a long-term storage stability as a two-pack type, and is very easy to handle in storage and molding operations. Further, when RIM molding is performed using the hybrid crosslinked resin composition of the present invention, it has high-speed moldability and excellent physical properties.

Continuation of front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C08G 18/00-18/87

Claims (6)

(57) [Claims] 1. An acid value of 2 mg KOH / g or less, and an OH value of 90
The main component is a mixture of an unsaturated polyester having a terminal hydroxy group and a vinyl compound having a concentration of about 150 mgKOH / g,
A resin component (1) containing 0.1 to 0.6% by weight of cobalt naphthenate and 0.01 to 0.2% by weight of cobalt acetylacetone, and a peroxyester 2.0 as an organic peroxide. To 8.0% by weight of the aromatic polyisocyanate component (2), and the equivalent ratio of hydroxy group to isocyanate group is OH / NCO = 1: 0.8 to
1: 1.5, characterized in that the storage stability is good, and the urethanization reaction between a hydroxy group and an isocyanate group and the radical crosslinking reaction with an unsaturated group proceed substantially simultaneously. Hybrid crosslinkable resin composition 2. The resin composition according to claim 1, wherein polyethylene glycol is used as a dissolving agent for cobalt acetylacetone. 3. The resin composition according to claim 1, wherein t-butyl peroxy laurate is used as the peroxy ester. 4. An acid value of 2 mg KOH / g or less and an OH value of 90
The main component is a mixture of an unsaturated polyester having a terminal hydroxy group and a vinyl compound having a concentration of about 150 mgKOH / g,
A resin component (1) containing 2.0 to 6.0% by weight of a solution in which 0.1 to 0.6% by weight of cobalt naphthenate and 2% by weight of acetylacetonate cobalt are dissolved in polyethylene glycol; An aromatic polyisocyanate component (2) containing 2.0 to 8.0% by weight of a peroxyester as an organic peroxide, when the equivalent ratio of the hydroxy group to the isocyanate group is OH / NCO; = 1 / 0.8-1
/1.5, and a urethanization reaction between a hydroxy group and an isocyanate group and a radical crosslinking reaction with an unsaturated group proceed substantially simultaneously using a reaction injection molding machine. Molding method of a hybrid crosslinked resin. 5. The molding method according to claim 4, wherein polyethylene glycol is used as a dissolving agent for cobalt acetylacetone. 6. The molding method according to claim 3, wherein t-butyl peroxy laurate is used as the peroxy ester.